Pneumatic level control



June 15. 1965 R. D. BECK PNEUMATIC LEVEL CONTROL Filed NOV. l0, 1961 INVEN TOR. RGLAND D. BECK ...IHIHIHHHHHHEU-.

l i i l IOWATER mvAcuUM VALVE; SOURCE ATTORNEY United States Patent O M 3,189,317 PNEUMATIC LEVEL CGNTRGL Roland D. Beck, Anaheim, Calif., assigner to Rohertshaw Controls Company, a corporation of Delaware Filed Nov. 10, 1961, Ser. No. 151,474 11 Claims. (Cl. 251-45) This invention relates to a water level control device and in particular to a pneumatic control for regulating the amount of water in a vessel such as a washing machine.

In the operation of modern washing machines, it is conventional practice to include some form of water level control which permits a flow of water into the washing machine and is operative in response to a predetermined level f the water to cut olf the ilow of water. In some prior art mechanisms, the water level control operates a switch, electrically connected to a solenoid actuated valve that is associated with the water filling apparatus. ln the use of pneumatically actuated devices, the water level control operates a valve which in turn controls the pneumatic actuation of water control apparatus. The present invention introduces a novel water level control of the pneumatic type which is more economical and more efcient than the prior art devices.

An object of this invention is to construct a pressure 'operafted device in order to control a pneumatic ow.

Another object of this invention is to utilize a thin flexible sheet as a Valving element to control a pneumatic vacuum flow.

This invention has another object in that a pressure responsive control device simultaneously actuates an electric switch and a pneumatic tow control element.

It is a further object of this invention to incorporate an electric switch and a pneumatic ow control into a compact structure in a water level control device.

A preferred embodiment of this invention includes a diaphragm adapted to operate a switch arm in response to a predetermined water level. The switch arm causes snap action of electrical contacts and is operatively connected to a valving element for simultaneous actuation thereof and thereby controls a pneumatic flow to a pneumatically operated control device.

Additional objects and advantages of this invention will become apparent from the following description taken in connection with the accompanying drawing wherein:

FIG. 1 is a plan View with parts removed of a control device embodying this invention;

FIG. 2 is a sectional view taken along line llell or" FIG. 1 but with parts added;

FIG. 3 is a schematic diagram on an enlarged scale of certain details of FIG. l; and

FlG. 4 is an exploded perspective showing the control element in a tilted position. i While the preferred embodiment of this invention is being described with relation to particular operations associated with a washing machine, it is to be understood that it has other uses and is readily adaptable to control the actuation of many other pneumatic mechanisms.

As is illustrated in FIGS, l and 2, a hollow casing 1li is interiorly separated by a diaphragm 12 into a pair of ,chambers 14 and 16. A tubing 18 has one end communicating with chamber 16 to form a sealed air chamber; the other end of tubing 18 includes any suitable means for compressing the air in tube 18 in response to the particular operation of the apparatus that is to be controlled. -For example, tubing 18 is adapted to be connected to a sump at the bottom of a washing machine (not shown) and as the water level in the machine increases, the air column in tubing 13 is compressed causing a pressure increase in chamber 16 which moves the diaphragm 12 to the right as viewed in FIG. 2.

i The side of diaphragm 12 facing the chamber 1e is ina a Ce l a,l9,al7

tegraliy secured to an actuating shaft Ztl which has a necked-down portion 22 intermediate its ends and a reduced portion 24 on its free end. The reduced portion 2d provides a mounting for an apertured retaining plate 2o. A similar retaining plate 2S is secured to a wall of the casing 1@ in alignment with the plate 2o and a coil spring 3i? is mounted in compression between the two piates 26 and 28. The coil spring Eil acts on the retaining plate 26 and shaft 2i) to exert a biasing force on the atmospheric pressure side of the diaphragm 12.

A switch arm 32 of a snap acting mechanism is disposed in the chamber 14 and has one end 3d secured to a supporting wall in the casing 10 and electrically connected to at common terminal post 35. The switch arm 32 is a flat rectangular strip having an opening 35 intermediate its ends. The edge of the opening nearest the mounting end is reduced to form a semi-circular edge 3S which is assembled in the necked-down portion 2?; of the shaft 2li. As is shown in FIG. 2, the width of the necked-down portion 22 is larger than the thickness of the switch arm 32 forming a lost motion connection with edge 38 so that the switch arm 32 of the snap acting mechanism will not be subjected to fluctuation and fluttering by the diaphragm 12. The opposite edge of the opening 36 has a projection dit which extends through an opening in one end of a U-shaped rolling spring 42. A similar opening in the other end of the U-shaped rolling spring l2 receives a projection i4 which is secured to an internal wall in the casing 10. When the switch arm 32 is flexed to the right as viewed in FlG. 2, the rolling spring #i2 is pivoted about the fixed projection 44, whereupon the free end i6 of switch arm 32 is moved with a snap action. The free end 46 of switch arm 32 carries a perpendicularly disposed blade 48 which has a contact titl for cooperation with the xed contact 52 secured to an internal wall of the casing 1i?.

The free end do of switch arm 32 carries a pin 54 which centrally extends through a plate 56 into a back-up block 5S. The plate Se is provided with a pair of spaced projections 69 and 62 which extend through the block 58 and terminate in spaced relation to the surface of the block 58. The block 5? consists of a piece of resilient porous material disposed between the plate 56 and a thin flexible valve element (sri which may be made of any suitable plastic material conforming to the same general outline as the block 53. A pair of spaced apertures on the valve disc o@ receive the ends of the projections ii and 62 whereby the flexible valve disc 64 is carried thereon. The flexible valve element @i is provided with a Iblister portion forming a channel 65 having a generally rectangular conguration. Spaced above the channel 66, the flexible valve element ed, the block 5?, and the plate do are drilled to define a through-bore dil.

The plate 55, the resilient porous block 53 and the valve element o45- are movable as a unit with the valve element being in surface contact with the face of a reading head or valve block 7o. The resilient porous block S8 acts as a plastic foam to hold the iiexible valve element 64 against the reading head itl in such a manner as to permit it to conform to any surface irregularities. A plurality of mounting apertures 'i2 permit the valve block 7@ to be securely fastened in the casing 1% as by cap screws. The surface of valve block f't) has a pair of aligned spaced recesses 74 and '76 of generally rectangular outline, in which the ends of the projections dit and 62 are respectively reciprocated to denne the limits of movement of the valve element 64. The valve block 7i? has a pair of conduits for conducting a pneumatic iiow through the valve block. "the irst conduit has one end 78 opening into the valve block surface and another end Sil opening to an exterior surface for suitable connection to a pneumatically operated control device such as a water valve for controlling amaai? a. iiow or Water to the washing machine. The second conduit has one end 52 opening into the valve block surface in aligned spaced relation to the rst openiing '73 and another end till opening to an exterior surface for suitable connection' to a vacuum source, such as a vacuum pump (not shown).

As is illustrated in FlG. 3, the thin tiexible valve element 6d slides relative to the valve surface of the valve block 7th so that in its upper poistion, the blister ed spans the conduit openings 78 and 82 and in its lower position, the conduit opening 32 is sealed and the conduit opening 78 communicates with the through-bore 68 so as to be subject to the atmospheric conditions in the casing ld. It should be noted that the through-bore 6d may ybe replaced by other' arrangements, for instance, the ilexible valve element ed could be so loosely carried by the pins d@ and 62 that communication between the conduit opening 73 and the interior of the casing l@ is establishedV by the space between the loose fitting valve element dll and the valve block 7d. Any such communication arrangement is permissible inasmuch as the use of vacuum will create a suction on the tlexible valve element @d in the area of its contact with the vacuum source port d2. Because of such suction and by the use of a liexible valve element, there is no leakage of the vacuum llow.

Since the atmosphere within the casing chamber )ld is utilized to establish atmospheric pressure in the pneumatically operated control device associated with the water flow valve, it is proposed to prevent impurities from clogging the flexible valve element 6d. The casing Mi is provided with a filter 9i), of any suitable liltering material, which is disposed in an inlet chamber adjacent a pair of atmospheric ports The interior of casing lil is sealed to the atmosphere except for the two ports 92 so that all air entering the chamber fifi must pass through the filtering material 9d,

ln operation of the above described water level control, when it is desired to till a washing machine with water, the various components are positioned as shown in FIG. 2 wherein the flexible valve element @d has its channel de spanning the two conduit openings 73 and 82. Thus, the pneumatically operated control device associated with the water flow valve is actuated by being subjected to a vacuum traced as followsrfrom the pneumatically operated control device, through the conduits till and 7d, under the flexible valve blister and through the conduits 52 and t-/l to a vacuum pump (not shown). As soon as the water in the washing machine reaches a predetermined level, the air pressure in casing chamber ltd increases and moves the diaphragm to the right as viewed in FIG. 2. The following movement of shaft Ztl causes the switch arm 32 to be actuated whereupon the ilexible valve element ed is moved with a snap action to its second position which is represented by the various components as shown in FIG. 3. ln the second position of the lexible valve element 6ft, the channel do is moved out of communication with the conduit openings 78 and S2, the conduit opening 82 is sealed by the suction on the iiexible valve element dit, and the conduit opening 7d is in communication with the atmosphere in the chamber 1A. The pneumatically operated control device is now subjected to atmospheric pressure and is returned to its normal position wherein the flow of water is cut oit to the washing machine.

W'hen the switch arm 32 is actuated, there is a simultaneous operation of the switch blade 4S causing a closing of an electric circuit for other control devices associated with a washing machine such as a timer motor of a programmer (not shown) to'initiate a programming function.

inasmuch as the present invention is subjected to many modifications and various changes in structural details, it

is intended that the foregoing description of the preferred embodiment shown in the drawing shall be interperted as illustrative and not in a limiting sense.

What is claimed is:

l. ln a pneumatic controlv device, the combination comprising a casing, conduits opening into said casing for permitting a vacuum iiow therethrough, diaphragm means operatively disposed in said casing, llexible valve means disposed adjacent the openings of said conduits, means interconnecting said diaphragm means and said ii-exible valve means for operating the same in response to operation of said diaphragm means, and channel means on said iiexible valve means for channelling the vacuum flow between the openings of said conduits, said iiexible valve means being liexed in response to suction of the vacuum iiow whereby there is no leakage of the vacuum ow.

2. ln a pneumatic control device, the combination comprising a casing, a valve block having a plurality of conduits for permitting a vacuum llow therethrough, diaphragm means operatively disposed in said casing, a ilexible valve element disposed for surface contact with said valve block, snap acting means operatively disposed between said diaphragm means and said flexible valve element for moving the same with a snap action, and an integrally formed blister on said iiexible Valve element defining a ilow channel for channelling the vacuum flow etween the conduits in said valve block, said ilexible valve element adhering to said valve block in response to suction of the vacuum flow whereby there is no leakage of the vacuum flow.

3. The combination as recited in claim 2 wherein lost motion means form a connection between said diaphragm means and said snap acting means.

It. In a pneumatic control device, the combination comprising a casing, a valve block in said casing having a plurality of conduits for conducting a vacuum iiow therethrough, diaphragm means in said casing, flexible valve means slidably disposed adjacent said valve block and controlling the vacuum flow through said conduits, a snap acting mechanism operatively disposed in said casing for actuation by said diaphragm means, an operative connection between said snap action mechanismand said ilexible valve means whereby said flexible valve means is operated by said snap acting mechanism, and a lost motion connection between said snap acting mechanism and said diaphragm means, said ilexible valve means being sealingly drawn into surface contact with said valve block in respense to suction of the vacuum flow to prevent leakage of the vacuum ilow.

5. The combination as recited in claim 4 wherein said flexible valve means includes channel means integrally formed on said flexible valve means for channelling a vacuum ilow between the conduits in said valve block.

6. in a pneumatic control device, the combination comprising a casing, diaphragm means in said casing, a snap acting mechanism operatively connected to said diaphragm means, a valve block having a plurality of conduits for permitting a vacuum iiow therethrough, a plate member operatively connected tosaid snap acting mechanism for movement thereby, a flexible valve element carried by said plate member and disposed for surface contact with said valve block, channel means integrally formed on said iiexible valve element for channelling a vacuum flow between said conduits, a resilient porous element disposed between said plate member and said flexible valve element, said resilient porous element maintaining said flexible valve element in surface contact withj said valve block, and means for guiding the movement of said iexible valve element relative to said valve block.

'7. The combination as recited in claim 6 wherein said yerdble valve element is provided with exhaust means movable into registry with one of said conduits whereby the said one conduit is subjected to atmospheric conditions in said casing. f

8. The combination as recited in claim '7 wherein said casing is provided with lilter means to filter the atmosphere entering said casing. l

9. In a pneumatic control device, the combination comprising a casing, a snap acting mechanism including an arm operatively disposed in said casing, diaphragm means operatively connected to said arm causing movement thereof between controlling positions, a valve block Xed in said casing having a plurality of conduits, one end of each conduit opening exteriorly of said casing for connection to a pneumatic flow, the other end of each conduit opening interiorly of said casing, a movable valve assembly unit slidably disposed on said valve block and including a plate member, a ilexible Valve member and a block of resilient porous material therebetween, said flexible valve member being biased into sliding surface contact with said valve block by said resilient porous material and being operatively disposed to control the said other end of each conduit, an operative connection between said arm and said plate member whereby movement of said arm elects operation of said valve assembly unit, and means for guiding the movement of said valve assembly unit relative to said valve block.

References Cited by the Examiner UNITED STATES PATENTS 2,636,093 4/53 Clark et al. 200-83 2,906,132 9/59 Moody etal 200-83 2,921,158 1/60 Taylor 200--83 3,021,823 2/ 62 Dinkelkamp 251-75 BERNARD A. GILHEANY, Primary Examiner. 

1. IN A PNEUMATIC CONTROL DEVICE, THE COMBINATION COMPRISING A CASING, CONDUITS OPENING INTO SAID CASING FOR PERMITTING A VACUUM FLOW THERETHROUGH, DIAPHRAGM MEANS OPERATIVELY DISPOSED IN SAID CASING, FLEXIBLE VALVE MEANS DISPOSED ADJACENT THE OPENINGS OF SAID CONDUITS, MEANS INTERCONNECTING SAID DIAPHRAGM MEANS AND SAID FLEXIBLE VALVE MEANS FOR OPERATING THE SAME IN RESPONSE TO OPERATION OF SAID DIAPHRAGM MEANS, AND CHANNEL MEANS ON SAID FLEXIBLE VALVE MEANS FOR CHANNELLING THE VACUUM FLOW BETWEEN THE OPENINGS OF SAID CONDUITS, SAID FLEXIBLE VALVE MEANS BEING FLEXED IN RESPONSE TO SUCTION OF THE VACUUM FLOW WHEREBY THERE IS NO LEAKAGE OF THE VACUUM FLOW. 